Producing hydrogen.



UNITED STATES PATENT OFFICE.

CARL BOSCH AND WILHELM WILD, OF LUDWIGSHAFEN-ON-THE-RHINE, GERMANY,

ASSIGNOBS TO BADISCHE ANILIN & SODA FABBIK, 0F LUDWIGSHAFEN-ON-THE- RHINE, GERMANY, A CORPORATION OF BADEN.

PRODUCING HYDROGEN.

No Drawing.

To all whom it may concern Be it known that we, CARL Boson and WILHELM WILD, citizens ofthe German Empire, residing at Ludwigshafen-on-the- "Rhine, Germany, have invented new and useful Improvements in Producing Hydrogen, of which the following is a specification. v

Attempts have been made to obtain pure hydrogen from water-gas by passing the Water-gas mixed with steam over a catalytic agent, so that the carbon monoxid is con- Verted into carbon dioxid and a further quantity of hydrogen is produced, the carbon dioxid and the excess of steam being removed from the gas by any suitable means. Such attempts have not hitherto led to satisfactory results, as the reaction proceeded only very incompletely.

We have now found that hydrogen can be obtained in an excellent manner by passing carbon monoxid, under which term we include carbon monoxid either as such or-in the form of a mixture containing carbon monoxid, such for instance as water-gas and generator-gas, in admixture with steam over a catalytic agent containing iron, under which term we include both metallic 1IOI1 and also iron oxid, provided the said iron be employed in a state of fine divlsion and also provided that during the production of the catalytic agent and also during the production of the hydrogen a temperature of about 650 C. is not substantially exceeded. During the reaction, the iron becomes more or less oxidized, say, to ferro-ferric oxid or even a mixture of oxids may be obtained. Any iron compound may be employed at starting which, during the reaction, gives rise to iron oxid. The iron oxid, or the iron or iron compound which gives rise to iron or iron oxid, can be supported on carriers, or can be employed in the condition of a fine powder, or in a fine porous condition,

and we prefer to make the catalytic agent in the form of porous lumps, briquets, or the like, because these are more easily arranged in the reaction space and the passage of the gas is rendered easy. Excellent results are obtained, for instance, b precipitating an'oxid, hydroxid, or car onate of iron from a solution of an iron salt, or by producing such compounds by heating a suitable salt, for instance oxalate, nitrate, or

Specification of Letters Patent.

Application filed June a0, 1913. Serial n. 776,548.

Patented Nov. 3, 1914.

the like, while avoiding too high a temperature, and then, if desired, af'ter m'oistening v and adding a suitable organic or inorganic diluent or binding agent, forming the prodduring their production, have been heated to higher temperatures than about 650 C. are not suitable for use according to this invention.

It is not essential to our invention that the practiser thereof shall be also the producer of the catalytic agent used, but it must be one which has been or shall be produced at a temperature not substantially exceeding 650 C. Such agent has been found to be non-sintered, and remains light and porous. R

The production of hydrogen, when employing a contact agent prepared as hereiniron oxidwhich are pro duced by burning iron pyrites and which,

before described, can be effected by mixing water-gas or other gas containing carbon monoxid with an excess of steam, passing the mixture over the contact agent at a raised temperature and then removing the carbon dioxid and the excess of steam. Good results are obtained at temperatures of from 400 to 500 C., or even at lower temperatures.

The followin examples will serve to illustrate methods of preparing and employing contact agents suitable for use according to this invention, but our invention is not confined to these examples. The parts are by weight.

Example 1: Add a solution of 100 parts of calcined sodium carbonate in 500 parts of water to a solution of 250 parts of ferrous sulfate in 500 parts of water. Filter oil the precipitate and wash it, and then,

without drying, mix it with 5 parts of slaked lime and dry until a paste is obtained which is thenkneaded, rolled out, cut into cubes, dried and heated at about 500 '0. Instead of slaked lime, an agent can be emplo ed which decomposes upon being heate such for instance as 14 parts of calcium nitrate, or a mixture of14 parts of calcium nitrate and '6 parts of ammonium nitrate. Example 2: Knead to a paste 10 parts of. finely divided iron oxid, such for mstance as the crocus martis of commerce, and a solution of 4 parts of aluminium nitrate in 4 parts of' water. Form this paste into pieces of the desired shape, which then dry and heat at 400 C. in a current'of air. In this example, the aluminium nitrate solution can be replaced by, for instance, a solution of 3.5' parts of magnesium nitrate in 3.5 parts of water.

--Example 3: Melt 40 parts of crystallized ferric nitrate at from 50 to 60 C. and stir in a mixture of 5 parts of caustic lime, 15 parts of water and 2 parts of caustic potash. Then mix this product with 50 parts ofprecipitate which has been obtained accordlng to the foregoing Example 1 and then dried, work the mixture in a kneading machine until a plastic mass is obtained, roll this out, cut it into cubes, dry it and heat at 500 C. If desired, pass over it a current of air orof carbon dioxid.

, the finest sieve and mix 10 parts thereof with one part of calcined magnesia, moistening it with a solution of 1 part of potassium carbonate in 1.6 parts of water. Press the mass into briquets, dry them and heat to about 600 C.

Example 5: Boil 2.5 parts of wheat starch with 15 parts of water until a stiff paste is obtained, stir in 1 part of potassium car-' bonate, add 20 parts of iron oxid obtained by carefully heating iron oxalate to a temperature not exceeding 600 C. Knead the whole until a plastic mass is obtained, form it into briquets, dry it and heat at about 600 C. In this example, gum t'ragacanth, dextrin, or gum arabic, can be employed inv stead of the starch.

Example 6: Mix 9 parts of ferric oxid hydrate with 1 part, or more, of ferric oX-- alate and then work up the mixture to a paste with a solution of 2.5 parts of calcium nitrate in 2 parts of water. Press the paste into suitable shapes and dry slowly in a current of air at about 500 G. Then pass a mixture of pure carbon monoxid with an excess of steam over the catalytic agent thus obtained, While maintaining a temperature of about 500 C. The excess of steam and,

the carbon dioxid which is formed can be removed from the final reaction gases in any suitable manner. If, in this example, generator gas be employed instead of pure carbon monoxid, a nnxture of mtrogen and hydrogen is. finally obtained.

Example 7 Pass a current of carbon monoxid mixed. with steam over iron in a state of fine division which has been preferably molded in a briquet press, at the same time gradually heating thecatalytic agent, but avoiding temperatures above 600 C.

Example 8: Mix ferric oxid hydrate with sufficient concentrated calcium nitrate solution to obtain a paste of suitable consistency, then bring this paste into suitableshapes and dry it in thecontact furnace while gradually raising the temperature to about 500 G. Then pass a mixture of carbon monoxid and steamover the catalytic agent, while avoiding temperatures above 600 0. Even if the gases are passed rapidly through the reaction furnace, an almost complete conversion of the carbon monoxid into carbon dioxid takes place. Exampler9: Heat ferric nitrate to about 200 C. sovas to-convert it into the oxid.

Moisten the latter with' aluminium nitrate solution and, then mold it into suitable shapes and. heat it at" about 400 C., until the nitrous gases are driven off. Then place the catalytic agent in the contact furnace and pass a mixture of carbon monoxid and steam through the furnace while avoiding temperatures above; 6006.

- Now whatfwe claim'is:

1. The processof producing hydrogen which consistsin passing a gas-containing or consisting of carbon monoxid admixture with steam over a catalytic agent containing divided iron oxid and which has been produced. at a temperature below 650 C.

2. The process of producing hydrogen which consists in passing a gas containing or consisting of carbon monoxid in admixture with steam at a temperature below 650 C. over a catalytic agent containing divided iron oxid and which has been produced at a temperature below 650 C.

3. The process of producing hydrogen which consists in passing a gas containing or consisting of carbon monoxid in admixture with steam over a non-sintered catalytic agent containing divided iron oxid.

In testimony whereof we have hereunto set our hands in the presence of two sub- J. ALEC. LLOYD, JOSEPH PFEIFFER. 

